Battery-driven screwdriver

ABSTRACT

A battery-operated screwdriver ( 10 ) with a housing ( 12, 18 ) with a grip ( 14 ), in particular with a fixedly built-in battery ( 40 ), and with charging contact tongues ( 37 ) for charging the battery ( 40 ), is designed as especially compact and lightweight because instead of a boxlike, standard ON/OFF switch, counterpart contacts ( 34 ) fixed to the tool are provided, to which a contact plate ( 32 ) that is movable by means of an ON/OFF trigger ( 26 ) and in the process is coupleable to the counterpart contacts ( 34 ) and upon their release is easily releasable, is assigned.

PRIOR ART

The present invention is based on a battery-operated screwdriver asgenerically defined by the preamble to claim 1.

Battery-operated screwdrivers with a power classification of between 2.4V and 3.6 V are known, for instance from European Patent Disclosure EP 1066 930. They usually have a plurality of Ni—Cd cells as energy storingmeans, an ON/OFF switch with a short pushbutton, and withoutcontinuously variable rpm regulation and with a switch for reversingfrom counterclockwise to clockwise rotation, a gear that steps down themotor rpm, in particular a planetary gear, and a motor with a standarddiameter of 27.5 mm. There are also rod-shaped and pistol-shapedversions, and versions with an adjustable-angle grip. For being charged,these devices are either connected to the charger device via a plug—asin the case of a cell phone or electric shaver—or via a mount withcontacts into which the device is placed. The mounts can be secured to awall, for instance, to make handling during charging easier.

To do this, the charging mode for the charger and for the electricalconnection must first be established, but this does not happenautomatically after every use. As a result, the device is often notready for use precisely when it is needed, and the familiar memoryeffect is a further disadvantage. Ni—Cd cells discharge after a certaintime unless power is supplied, and even unused battery-operatedscrewdrivers are soon partly discharged. If they are recharged becausethey have been partly discharged, then because of the memory effect,after the charging operation, only the difference amounting to the newcharging amount is available—and hence only reduced power is available.

Another disadvantage of the known battery-operated screwdrivers is theirvolumetric size, because they contain large structural components, suchas the gear, the switch system, and the battery in the form of Ni—Cdcells, whose size known as “4/5 Sub-C”, when located in the grip,impairs both ergonomics and usability, since narrow, angled screwinglocations are inaccessible.

ADVANTAGES OF THE INVENTION

By the use of only a single long, slender lithium-ion (Li-ion) cell,fixedly built into the grip of the battery-operated screwdriver, insteadof a plurality of 4/5 Sub-C nickel-cadmium cells as a battery, anespecially small grip circumference can be attained. A markedly reduced,extremely handy structural size of the “lady's revolver format” ismoreover attained by replacing a conventional, boxlike switch unit witha contact plate that takes up only about 10% of the volume of the switchunit and is connected to the ON/OFF trigger and electrically connectstwo counterpart contacts to one another upon displacement of the button.For this purpose, the contact plate is screwed into the ON/OFF trigger.

Two relatively large, hard spiral springs keep the ON/OFF triggerprestressed in its OFF position, and by rapid opening and closing of thecontacts, given the high impedance that increases over the service life,prevent it from being fused to the contact plate.

The especially long ON/OFF trigger, extending over nearly the entireinside of the grip, has a short actuation stroke, and as a result isespecially easily actuatable at any arbitrary point in a way thatreliably switches ON the motor. As a result—regardless of the actuationposition—only slight user forces are necessary, and the device can beconveniently switched ON in virtually any position of the user's hand.To improve the guidance of the ON/OFF trigger relative to the housing,the ON/OFF trigger has two lateral guide tongues on its inside, whichare braced in the housing in a slidingly supported way.

A further volumetric reduction of the battery-operated screwdriver isattained by means of the compact design of the gear and the gearbox; thegear, as a planetary gear, is merely placed in the cylindrical gearboxand is kept from falling out by an axial securing plate. The gearboxinternal toothing serves itself as a sun wheel.

Because the end of the motor shaft associated with the gear has a flatface, and the corresponding engagement opening of the gear input shafthas the complementary negative shape, a simple, easily assembled compactcoupling between the motor and the gear is created, which also allowscourse tolerances and functions reliably.

Because the motor housing is composed of half-shells split in themiddle, which in tonglike fashion embrace the cylindrical gearbox fromboth sides with radially inward-protruding support tongues and keep itcentered in the assembly position, the gearbox can be joined preciselyand securely to the motor housing without separate fastening or guideelements such as screws, centering pins, or overlooking elements.

A further reduction in weight and volume of the battery-operatedscrewdriver is attained by omitting a chuck; by means of a hexagonalsocket of the power takeoff shaft—fitting corresponding screw or borebits with a hexagonal shank—these tools can be changed quickly andsimply.

Since the lithium-ion cell has almost no self-discharge, thebattery-operated screwdriver is fully ready for use even after longintervals between uses; in intervals between uses, the battery-operatedscrewdriver can rest for an arbitrarily long time on the charging shellin the charging mode. The charging shell can be placed, standingsecurely, on a level shelf and need not be secured or firmly held whenthe battery-operated screwdriver is removed. As a result, it can alwaysbe removed quickly with only one hand; no plug has to be unplugged andno mount has to be removed. Moreover, it is automatically assured at alltimes that the battery-operated screwdriver is charged.

The compact lithium-ion cell sits without play, positionally secured andbraced, in the interior of the half-shell-like grip regions, and contactlugs with electric lead lines are soldered by their end regions to thecircuit board. The lithium-ion cell is integrated into the strengthstructure the grip and increases its dimensional stability while usingonly little material for the half-shells of the housing.

The circuit board intended for control is the chassis for the turn-oncontacts, the charging contact tongues, the slide switch for reversingthe direction, and the two light-emitting diodes for indicating thedirection of rotation, and the control means for the charging anddischarging current of the lithium-ion cell. The circuit board is alsolocated longitudinally in the interior of the grip, in the form of anadditional crosswise rib integrated into the strength structure of thehousing or grip, and increases the bending strength of the housing orgrip considerably.

Instead of a boxlike ON/OFF switch that is typical in this class, whichhas one position each for clockwise and counterclockwise operation, theconcept of a separate clockwise/counterclockwise preselection wasadopted. While in previous drilling screwdrivers, a separate structuralgroup is placed for this purpose on the boxlike mains switch, in thepresent case a simpler and less-expensive slide switch, which issoldered onto the circuit board and for instance takes the form ofmass-produced goods from the electronics trade—controllable by hand byway of the usual slides—and thus a simply constructed means forreversing the direction of rotation, is created.

The ON/OFF trigger and the direction of rotation reversal are designedsuch that on the one hand, when the ON/OFF trigger is depressed, thedirection of rotation reversing means is blocked and cannot be moved,and on the other, the ON/OFF trigger is blocked and cannot be pressedinto the activation position, when the direction of rotation reversingmeans is in its middle position, which is the recommended position fortransport.

The charging contact tongues soldered to the circuit board protrudethrough openings in the lower end of the grip and are contacted, in thecharging position, by counterpart contacts of the charging shell; noadditional cords or coupling plugs have to be actuated.

Depending on the direction of rotation of the motor, a green or redlight-emitting diode soldered to the circuit board lights up. Theselight-emitting diodes are visible through openings in the housing thatare covered by a transparent plastic part acting as a window.

The gearbox is simultaneously the outer wheel of the planetary gear. Asa result, one additional component is dispensed with, and the devicebecomes slender and compact, with a small corner size (spindle axis tothe outer contour). The tooth cross sections or the tooth height of theouter wheel of the planetary gear (the gearbox) are at the same a stopfor a securing disk, which serves as an axial securing means and formsthe boundary, toward the motor, of the planet wheels of the first stage.The securing disk has two vanes, protruding past its circumference,which can be locked in the manner of a bayonet mount in twocorresponding indentations on the gearbox and can be secured againstaxial release by rotation in an adjoining annular groove. At the sametime, this serves as a securing means during shipping, for the drivesthat are deliverable separately. The disk is held in the built-in stateby its vanes between the motor and the gearbox. A securing disk withprotruding, angled vanes that can be secured in the indentations bybeing pressed into them can also be used.

The planetary gear is provided with an auto-locking system, that is, bythe self-locking drive spindle upon rotation thereof by force exertedfrom outside. Its gearbox has axial extensions at the top and bottomtoward the motor, with an annular groove and an annular bead. Thisannular groove is engaged by annular beads of the half-shells of themotor housing, which have a complementary counterpart profile. Thus thegearbox is received and axially fixed without further components such asscrews, rivets, or overlooking tongues. Laterally, where the gear hasrecesses between these extensions, axial counterpart extensions of thehalf-shells protrude into the recesses. This arrangement serves tosecure the gearbox against relative rotation with respect to the motorhousing—without using separate components. The axial extensions areasymmetrical, to assure unambiguous assembly.

The gearbox, the circuit board with the battery, motor, light-emittingdiodes and electrical elements, as well as the switch pushbutton withthe contact plate and springs and the transparent plastic part areplaced in a first half-shell, closed with the second half-shell, andclosed with only four identical screws and thus completely assembled andresult in a very inexpensive embodiment.

The compact design makes it possible to hold the device in one hand, atthe front of the gearbox or on the adjoining motor housing, in such away that a screw can be held against the bit with the index finger, andat the same time the large-area ON/OFF trigger can be comfortablyoperated with the other fingers, and the free hand can furthermore holdthe workpiece.

Because of the large-area rubber sheathing with a bumpy surface over theentire grip region, the battery-operated screwdriver fits especiallysecurely in the user's hand.

DRAWINGS

The invention is described below in further detail in terms of anexemplary embodiment and the associated drawings.

Shown are:

FIG. 1, a side view of the partly open battery-operated screwdriver;

FIG. 2, a front view of the battery-operated screwdriver;

FIG. 3, a side view of the battery-operated screwdriver, positioned in acharging shell;

FIG. 4, an enlarged detail of FIG. 1 looking toward the switch button;

FIG. 5, an enlarged detail of the gearbox of FIG. 1;

FIG. 6, a view as in FIG. 1, slightly rotated;

FIG. 7, a view as in FIG. 6, slightly rotated;

FIG. 8, a three-dimensional view of the gearbox from the front;

FIG. 9, a three-dimensional view of the gear from behind; and

FIG. 10, a three-dimensional view of the charging shell from above.

DESCRIPTION OF THE EXEMPLARY EMBODIMENT

FIG. 1 shows a pistol-shaped battery-operated screwdriver 10, with amotor housing 12 aligned in the screwing direction and with a grip 14 atan angle from the motor housing. The motor housing 12 and grip 14 areformed of two half-shells 16, 17, which can be joined together, bracedtightly against one another, in a center plane 15. To that end, fourscrews extend through bores in one half-shell 17 into four screw domes19 of the other half-shell 16 and hold the two half-shells firmlyagainst one another.

An ON/OFF trigger 26 is located so that it extends over merely theentire internal length of the grip 14. Toward the tool, the ON/OFFtrigger 26, together with a screwed-on contact plate 32 and inconjunction with counterpart contacts 34 fixedly located in the tool,forms an ON/OFF switch, making a separate, commercially conventionalboxlike standard switch or button unnecessary. The ON/OFF trigger 26,because of its special length, makes it convenient to switch thebattery-operated screwdriver ON and OFF, even in complicated holdingpositions of the battery-operated screwdriver 10. On its long sides, itis provided with lateral support tongues 27 that enter into the grip 14and form a secure guide on corresponding counterpart faces of thehalf-shells 16, 17 and make precise, play-free motion back and forthpossible.

Via two hard compression springs 28, 30, the ON/OFF trigger 26 iselastically braced on the grip 14, so that once the tool is switched on,the springs 28, 30 automatically move the ON/OFF trigger 26, when it islet go, into its OFF position and disconnect the contacts 32, 34 andstop the motor motion. The actuation stroke is limited by stops, notidentified by reference numerals, and at a length of 1 to 4 mm is veryshort and easy to control.

To enable the ON/OFF trigger 26 to move into the motor housing 12, asuitable opening 29 is provided, half of which is located in each of thehalf-shells 16, 17; this opening closely surrounds the ON/OFF trigger 26in a way that guides it in shaftlike fashion. On its face end toward thegrip 14, the ON/OFF trigger 26 has one longitudinally protruding tongueat the top and another at the bottom; these tongues protrude past theopening 29 and are braced from inside on its edge and firmly hold theON/OFF trigger 26, bracing it, thereon in the OFF position and keep itfrom being released from the housing 12.

The counterpart contacts 34 associated with the contact plate 32 arelocated on an elongated circuit board 36, extending in the interior ofthe grip 14, diametrically opposite the contact plate 32 and in itsreciprocation region. The circuit board 36, in its lower region, alsohas two symmetrically located charging contact tongues 37, which extendat a right angle from the plane of the circuit board 36 and then on eachend form outward-angled, large supporting surfaces. These surfaces passthrough each half-shell 16, 17 symmetrically to the center plane 15 inthe lower end of the grip 14. At each passage point, they are eachembedded in a respective indentation, or “countersunk”, inside the gripcontour and are accessible to the outward-protruding charging contacts23 of the charging shell 22, which fit over them in the charging statewhen placed on the charging shell 22 and are braced, securely contacted,because of their resilient disposition.

The circuit board 36 also has interference resistors and capacitors, notidentified by reference numeral, approximately centrally, flat and nearthe surface, and in its upper region it also has the slide switch 38, aswell as two light-emitting diodes 57, 58 on the upper end for visuallyindicating the direction of rotation.

The circuit board 36 is located with its long side parallel to the grip14 and its short side transverse to the center plane 15 and is thusclamped without play in groovelike recesses, not identified by referencenumeral, in the two half-shells 16, 17 in such a way that it is bracedfrom inside against the half-shells 16, 17 and as a result forms areinforcing rib in the grip 14. A lithium-ion cell, with its familiaradvantages, is placed as a battery 40 in the grip 14, parallel to thecircuit board 36; this cell is embraced in tonglike fashion andpositionally secured in the assembled state by the two half-shells 16,17 and is thus integrated with the strength structure of the housing 12.At the top and bottom, the battery 40 has a respective contact plate 42,43, which serves as a soldering lug and is wired to the circuit board36.

Above the ON/OFF trigger 26—in the nip between the angled grip 14 andthe motor housing 12—a slide button 39 is located transversely to thecenter plane 15 of the motor housing 12 and can be displaced back andforth through lateral openings, not identified by reference numeral, inthe half-shells 16, 17. The slide button 39, with an approximatelycentral recess not identified by reference numeral, extends in forklikefashion around a slide device 41 of a boxlike slide switch 38 fixed inthe upper region of the circuit board 36. The slide device 41 seated onthe slide switch 38 is adjustable via the slide button 39 into theoutermost left and right side positions and into a middle position.

A direct-current motor 46 in the front region of the motor housing 12 isembraced in tonglike fashion by the half-shells 16, 17 after they havebeen installed and is held in its working position without play,oriented in an aligned fashion, parallel to the gearbox 18 placed in themotor housing 12. The motor 46 has one rear and one front steplike motorcollar 48, 49, from which the rear and front ends, respectively, of themotor shaft 45 emerge. The motor 46 is supported, centered in bracedfashion, via its front and rear motor collars 48, 49 in correspondingbearing-blocklike ribs of the half-shells 16, 17. The front end 47 ofthe motor shaft 45 is provided with a flat face or a double flat, inparticular by creative shaping, and thus in the installed positionengages a corresponding flattened recess of an input pinion 66 of thegear 65, designed as a planetary gear, that is located in the gearbox18. A easily assembled force-locking coupling with a wide dimensionaltolerance is thus created, and the motor 46 with the gear 65 or thegearbox 18 can easily be put together and placed in put-together form,for further installation, into one of the half-shells 16, 17.

On the face end, the two half-shells 16, 17 embrace the gearbox 18 intonglike and form-locking fashion, the gearbox being installed as aseparate cylindrical structural group, and hold it firmly without play.In two axial, tonguelike, partly cylindrical extensions 60 that extendtoward the motor housing 12, the gearbox has a housing annular groove54, which is bounded by an annular bead 55. The annular bead 55 engagesa fitting counterpart annular groove 56 on the inside of the face end ofthe half-shells 16, 17 of the motor housing 12, and fitting counterpartannular beads 53 of the half-shells 16, 17 fit in form-locking fashioninto the housing annular groove 54 of the gearbox 18.

Counterpart extensions 61 bent at an angle, crosswise to thelongitudinal direction of the motor housing 12, engage the twoasymmetrical recesses between the two extensions 60 of the gearbox 18 ina way that is secure against incorrect installation and without play;these counterpart extensions also in bearing-blocklike fashion brace themotor collar 58 of the motor 46 in centering fashion, so that thiscollar is likewise integrated with the strength structure of the motorhousing 12. Separate fastening elements, such as screws or the like, arethen unnecessary. This makes for easier assembly with a reduced numberof individual parts.

At the top rear, the motor housing 12 has an emplaced, transparentwindow 59, which extends longitudinally in the parting plane and issplit in the middle. Through two openings in the half-shells 16, 17, itprovides a view to one blue and one red light-emitting diode 57, 58,each of which is associated to one direction of rotation of the motorshaft 45 and light up when the direction of rotation occurs.

From the gearbox 18, which tapers at the front into a rounded cone, apower takeoff spindle 20 emerges at the front; it is designed on theface end as a hexagonal socket 21, for receiving suitable standard bits.The hexagonal socket 21 is provided with means that firmly secure aninserted screw bit or drill bit against being lost, so that a certainresistance has to be overcome by hand to remove the bit axially.

FIG. 3 shows a relatively narrow, boxlike charging shell 22, whose outercontour is adapted with oblique surfaces to the pistol-like inner andouter contour of the battery-operated screwdriver 10 and is indented ingroovelike fashion. The battery-operated screwdriver 10 can thereforeenter without play, with its inside, into beds 25 of appropriate fit forthe grip 14 and for the motor and gearbox 12 and 18, and can rest insecured fashion by its own weight; the contacting between its chargingcontact tongues 38 and the charging contacts 23 of the charging shell 22is especially secure.

The charging contacts 23 protrude from the contour of the charging shell23, so that the battery-operated screwdriver 10 with its grip 14 locksinto a corresponding recess in the charging shell 12 and in the processis braced by its own weight, with its charging contact tongues 37, onthe resilient charging contacts 23 of the charging shell 22. Simplyplacing the battery-operated screwdriver 10 on the charging shell 22immediately establishes the charging state, with an audible click.

On the left in the viewing direction, the charging shell 22 has anelectrical plug contact, not identified by reference numeral, forintroducing an electrical connection cord 24 for supplying power to thecharging shell 22, which in its rear region, associated with the grip 14of the battery-operated screwdriver 10, has a charge monitoring light 71and a perpendicular insertion opening 73 for retaining a screw bit orbore bit.

With its inside, and particularly with its ON/OFF trigger 26, thebattery-operated screwdriver 10 rests on the top of a charging shell 22,where on being put in place it automatically assumes a secure chargingposition, as long as the charging shell 22 is connected by the cord 24to a suitable power supply.

FIG. 4 shows an enlarged detail of the first half-shell 16 with theindividual parts inserted as in FIG. 1; this clearly shows the design ofthe battery 40 with its adjacent parts and of the circuit board 36 withthe parts secured to it as well as of the ON/OFF trigger 26.

FIG. 5 shows a detail of the front region of the battery-operatedscrewdriver 10, with the lower half-shell 16, looking toward the motor46 and the gearbox 18—put in place in form-locking fashion.

FIG. 6 shows a perspective view corresponding to FIG. 1, with thecorresponding details of FIG. 1; beyond these details, the slide button39 for reversing the direction of rotation can be seen more clearly,which in its middle position simultaneously forms an activation blockfor actuating the ON/OFF trigger 26. As a result, in this position, anunintentional actuation, for instance while the tool is being carried ina pants pocket, is not possible.

FIG. 7 shows a further three-dimensional view corresponding to FIGS. 1and 6; the details described in conjunction with them will not berepeated here but are intended to improve comprehension of them.

FIG. 8 shows the face end of the gearbox 18 as a detail, with thebuilt-in gear 65, and the power takeoff shaft 20, protruding from thefront, with the hexagonal socket 21 and the axial extensions 60,protruding to the rear from the gearbox 18, in which regular ovalindentations 70 on the outside of the gearbox 18 improve its grip.

FIG. 9 shows the gearbox 18 of FIG. 8, which is cylindrical at the rear,in a view from behind; the two axial extensions 60 and theirinterstices, a spring disk 62 with a center opening 63, the disk beinglocked in the interior of the gearbox 18 and extending over its entireinside diameter, are visible.

The spring disk 62 has radially protruding vanes 64, with which it canbe placed in bayonetlike fashion in corresponding recesses in thecircumference of the rear end of the gearbox 18 and locked therein byrotation or wedging.

Through the center opening 63, the input shaft 66 of the gear 65 forengaging the motor shaft 47 is accessible and can be coupled to theflattened end thereof, so that its rotary slaving can be effectedsecurely. The input shaft 66 has a center recess 68, which forms thenegative shape of the flattened end of the motor shaft 47.

FIG. 10 is a plan view from above on the charging shell 22, lookingtoward the bed 25, which is subdivided into a grip bed 251 and a gearboxbed 252, so that the battery-operated screwdriver 10 can be placed flushand virtually without play in the charging shell 22, unambiguously andin a foolproof way, such that it rests securely on it and its chargingcontact tongues 37 (FIGS. 1, 2, 4, 6, 7) enter into a secure contactwith the charging contacts 23 of the charging shell 22.

1. A battery-operated screwdriver (10), having a housing (12, 18) with agrip (14) with a battery (40) that in particular is fixedly built in,and with charging contact tongues (37) for charging the battery (40),wherein counterpart contacts (34) solidly connected to the tool, inconjunction with a contact plate (32), which is movable by means of anON/OFF trigger (26) and is coupleable to the counterpart contacts (34)and is easily releasable upon release of the ON/OFF trigger (26), serveas ON/OFF switches.
 2. The battery-operated screwdriver according toclaim 1, wherein the ON/OFF trigger (26) extends over nearly the entirelength of the grip (14) and is actuatable for switching ON the tool atan arbitrary point in conjunction with a short actuation stroke of 1 to5 mm, preferably 2 mm.
 3. The battery-operated screwdriver according toclaim 1, wherein the ON/OFF trigger (26) is braced in prestressedfashion counter to the actuation direction on the housing (12) by meansof two spiral springs (28, 30).
 4. The battery-operated screwdriveraccording to claim 1, wherein only a single, elongated, slenderlithium-ion (Li-ion) cell, as the battery (40), is located in the grip(14).
 5. The battery-operated screwdriver according to claim 1, whereinits work spindle (20), instead of a chuck, has a polygonal socket (21)for the use of fitting screw or bore bits with a polygonal shank.
 6. Thebattery-operated screwdriver according to the preamble to claim 1,wherein the battery (40) is positionally secured, held in tonglikefashion, in the interior of the grip (14) by means of half-shells (16,17) of the housing (12) and serves as a means for stiffening the housingstructure.
 7. The battery-operated screwdriver according to claim 1,wherein a circuit board (36) serving to receive electrical contacts (32,34) and control elements extends along the grip (14) in its interiorand—held in tonglike fashion by means of the half-shells (16, 17) of thehousing (12)—serves to stiffen the housing (12).
 8. The battery-operatedscrewdriver according to claim 8, wherein the circuit board (36) hascharging contact tongues (38), counterpart contacts (34) for switching amotor (46) ON, the battery (40), a slide switch (38) for reversing thedirection of rotation of the motor (46), two light-emitting diodes (57,58) for indicating the direction of rotation, and means for controllingthe charging and discharging current of the battery (40).
 9. Thebattery-operated screwdriver according to claim 1, wherein it has means(38), separate from the ON/OFF trigger (26), for reversing fromclockwise to counterclockwise operation.
 10. The battery-operatedscrewdriver according to claim 8, wherein for reversing from clockwiseto counterclockwise operation, a slide switch (38) soldered to thecircuit board (36) is provided, which is actuated via a slide button(39) that in particular is longitudinally displaceable.
 11. Thebattery-operated screwdriver according to claim 1, wherein when theON/OFF trigger (26) is depressed, the slide switch (38) is blocked, andthe ON/OFF trigger (26) is blocked whenever the slide button (39) is inthe middle position.
 12. The battery-operated screwdriver according toclaim 1, wherein after the emplacement of a circuit board (36), carryingthe electrical parts or wired to them, with the battery (40), a motor(46), an ON/OFF trigger (26), a slide switch (38) with a slide button(39), two light-emitting diodes (57, 58), and a transparent plastic partacting as a window (59), as well as the emplacement of the gearbox (18)into the first half-shell (16) and the ensuing joining together above itof the second half-shell (17) and screwing the half-shells (16, 17)together with only four identical screws, the battery-operatedscrewdriver is fully assembled.
 13. The battery-operated screwdriveraccording to claim 1, wherein a large-area rubber sheathing with a bumpystructure protruding in beadlike fashion is located on each half-shell(16, 17) in the region of the grip (14).